The media and public were admitted on Monday at the opening of the trial but are being barred from the courtroom while a daughter and son's testimony is played.

A psychiatric expert is expected to testify on Wednesday and two reports by technical experts regarding the cellar in which the defendant locked his daughter for 24 years will also be read out to the court.

Mr Fritzl, his lawyer and the prosecution all agreed to the reading of the experts' opinion rather than their appearance at the trial, Mr Cutka said.

No details are being given of the videotaped testimony or Mr Fritzl's possible responses to it.

"The defendant was questioned about the issues that came up in the testimonies, and he gave his views," the court spokesman told a news conference.

"The defendant followed the recorded testimony attentively."

Prison official Erich Huber-Guensthofer confirmed that a psychiatrist had been caring for Mr Fritzl before and during the trial to ensure he did not attempt suicide.

"He is accompanying him during the trial and is available for talks during trial breaks and after the day's proceedings," he said.

Mystery visit

Mr Fritzl is alleged in 1984 to have lured his daughter into a cellar with windowless soundproofed chambers beneath their house, to have imprisoned her there and raped her repeatedly over a number of years.

A bank of TV cameras faces the courthouse in St Poelten

The daughter and three of her seven children fathered by Mr Fritzl were kept captive in the cellar until the case came to light in April last year, when one of the children became seriously ill and was taken to hospital.

Mr Fritzl is accused of murdering one of the newborn twin boys his daughter gave birth to in 1996, having failed to arrange medical care for the ailing infant.

Some legal experts have said it may be hard to prove the murder charge but the charge of enslavement carries a maximum penalty of 20 years, and some of the other charges carry a sentence of up to 15 years.

Details have emerged of a bizarre visit that Mr Fritzl received recently in jail by a man claiming to be an estate agent.

The visit was cut short after officials realised the man was trying to pursue "very personal" business with Mr Fritzl, Mr Huber-Guensthofer said, without elaborating.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.